require 'haml/helpers'
require 'haml/buffer'
require 'haml/precompiler'
require 'haml/filters'
require 'haml/error'
module Haml
# This is the frontend for using Haml programmatically.
# It can be directly used by the user by creating a
# new instance and calling \{#render} to render the template.
# For example:
#
# template = File.read('templates/really_cool_template.haml')
# haml_engine = Haml::Engine.new(template)
# output = haml_engine.render
# puts output
class Engine
include Precompiler
# The options hash.
# See {file:HAML_REFERENCE.md#haml_options the Haml options documentation}.
#
# @return [{Symbol => Object}]
attr_accessor :options
# The indentation used in the Haml document,
# or `nil` if the indentation is ambiguous
# (for example, for a single-level document).
#
# @return [String]
attr_accessor :indentation
# @return [Boolean] Whether or not the format is XHTML.
def xhtml?
not html?
end
# @return [Boolean] Whether or not the format is any flavor of HTML.
def html?
html4? or html5?
end
# @return [Boolean] Whether or not the format is HTML4.
def html4?
@options[:format] == :html4
end
# @return [Boolean] Whether or not the format is HTML5.
def html5?
@options[:format] == :html5
end
# The source code that is evaluated to produce the Haml document.
#
# In Ruby 1.9, this is automatically converted to the correct encoding
# (see {file:HAML_REFERENCE.md#encoding-option the `:encoding` option}).
#
# @return [String]
def precompiled
return @precompiled if ruby1_8?
encoding = Encoding.find(@options[:encoding])
return @precompiled.force_encoding(encoding) if encoding == Encoding::BINARY
return @precompiled.encode(encoding)
end
# Precompiles the Haml template.
#
# @param template [String] The Haml template
# @param options [{Symbol => Object}] An options hash;
# see {file:HAML_REFERENCE.md#haml_options the Haml options documentation}
# @raise [Haml::Error] if there's a Haml syntax error in the template
def initialize(template, options = {})
@options = {
:suppress_eval => false,
:attr_wrapper => "'",
# Don't forget to update the docs in doc-src/HAML_REFERENCE.md
# if you update these
:autoclose => %w[meta img link br hr input area param col base],
:preserve => %w[textarea pre code],
:filename => '(haml)',
:line => 1,
:ugly => false,
:format => :xhtml,
:escape_html => false,
}
template = check_haml_encoding(template) do |msg, line|
raise Haml::Error.new(msg, line)
end
unless ruby1_8?
@options[:encoding] = Encoding.default_internal || template.encoding
@options[:encoding] = "utf-8" if @options[:encoding].name == "US-ASCII"
end
@options.merge! options.reject {|k, v| v.nil?}
@index = 0
unless [:xhtml, :html4, :html5].include?(@options[:format])
raise Haml::Error, "Invalid format #{@options[:format].inspect}"
end
if @options[:encoding] && @options[:encoding].is_a?(Encoding)
@options[:encoding] = @options[:encoding].name
end
# :eod is a special end-of-document marker
@template = (template.rstrip).split(/\r\n|\r|\n/) + [:eod, :eod]
@template_index = 0
@to_close_stack = []
@output_tabs = 0
@template_tabs = 0
@flat = false
@newlines = 0
@precompiled = ''
@to_merge = []
@tab_change = 0
precompile
rescue Haml::Error => e
if @index || e.line
e.backtrace.unshift "#{@options[:filename]}:#{(e.line ? e.line + 1 : @index) + @options[:line] - 1}"
end
raise
end
# Processes the template and returns the result as a string.
#
# `scope` is the context in which the template is evaluated.
# If it's a `Binding` or `Proc` object,
# Haml uses it as the second argument to `Kernel#eval`;
# otherwise, Haml just uses its `#instance_eval` context.
#
# Note that Haml modifies the evaluation context
# (either the scope object or the `self` object of the scope binding).
# It extends {Haml::Helpers}, and various instance variables are set
# (all prefixed with `haml_`).
# For example:
#
# s = "foobar"
# Haml::Engine.new("%p= upcase").render(s) #=> "<p>FOOBAR</p>"
#
# # s now extends Haml::Helpers
# s.respond_to?(:html_attrs) #=> true
#
# `locals` is a hash of local variables to make available to the template.
# For example:
#
# Haml::Engine.new("%p= foo").render(Object.new, :foo => "Hello, world!") #=> "<p>Hello, world!</p>"
#
# If a block is passed to render,
# that block is run when `yield` is called
# within the template.
#
# Due to some Ruby quirks,
# if `scope` is a `Binding` or `Proc` object and a block is given,
# the evaluation context may not be quite what the user expects.
# In particular, it's equivalent to passing `eval("self", scope)` as `scope`.
# This won't have an effect in most cases,
# but if you're relying on local variables defined in the context of `scope`,
# they won't work.
#
# @param scope [Binding, Proc, Object] The context in which the template is evaluated
# @param locals [{Symbol => Object}] Local variables that will be made available
# to the template
# @param block [#to_proc] A block that can be yielded to within the template
# @return [String] The rendered template
def render(scope = Object.new, locals = {}, &block)
buffer = Haml::Buffer.new(scope.instance_variable_get('@haml_buffer'), options_for_buffer)
if scope.is_a?(Binding) || scope.is_a?(Proc)
scope_object = eval("self", scope)
scope = scope_object.instance_eval{binding} if block_given?
else
scope_object = scope
scope = scope_object.instance_eval{binding}
end
set_locals(locals.merge(:_hamlout => buffer, :_erbout => buffer.buffer), scope, scope_object)
scope_object.instance_eval do
extend Haml::Helpers
@haml_buffer = buffer
end
eval(precompiled + ";" + precompiled_method_return_value,
scope, @options[:filename], @options[:line])
ensure
# Get rid of the current buffer
scope_object.instance_eval do
@haml_buffer = buffer.upper
end
end
alias_method :to_html, :render
# Returns a proc that, when called,
# renders the template and returns the result as a string.
#
# `scope` works the same as it does for render.
#
# The first argument of the returned proc is a hash of local variable names to values.
# However, due to an unfortunate Ruby quirk,
# the local variables which can be assigned must be pre-declared.
# This is done with the `local_names` argument.
# For example:
#
# # This works
# Haml::Engine.new("%p= foo").render_proc(Object.new, :foo).call :foo => "Hello!"
# #=> "<p>Hello!</p>"
#
# # This doesn't
# Haml::Engine.new("%p= foo").render_proc.call :foo => "Hello!"
# #=> NameError: undefined local variable or method `foo'
#
# The proc doesn't take a block; any yields in the template will fail.
#
# @param scope [Binding, Proc, Object] The context in which the template is evaluated
# @param local_names [Array<Symbol>] The names of the locals that can be passed to the proc
# @return [Proc] The proc that will run the template
def render_proc(scope = Object.new, *local_names)
if scope.is_a?(Binding) || scope.is_a?(Proc)
scope_object = eval("self", scope)
else
scope_object = scope
scope = scope_object.instance_eval{binding}
end
eval("Proc.new { |*_haml_locals| _haml_locals = _haml_locals[0] || {};" +
precompiled_with_ambles(local_names) + "}\n", scope, @options[:filename], @options[:line])
end
# Defines a method on `object` with the given name
# that renders the template and returns the result as a string.
#
# If `object` is a class or module,
# the method will instead by defined as an instance method.
# For example:
#
# t = Time.now
# Haml::Engine.new("%p\n Today's date is\n .date= self.to_s").def_method(t, :render)
# t.render #=> "<p>\n Today's date is\n <div class='date'>Fri Nov 23 18:28:29 -0800 2007</div>\n</p>\n"
#
# Haml::Engine.new(".upcased= upcase").def_method(String, :upcased_div)
# "foobar".upcased_div #=> "<div class='upcased'>FOOBAR</div>\n"
#
# The first argument of the defined method is a hash of local variable names to values.
# However, due to an unfortunate Ruby quirk,
# the local variables which can be assigned must be pre-declared.
# This is done with the `local_names` argument.
# For example:
#
# # This works
# obj = Object.new
# Haml::Engine.new("%p= foo").def_method(obj, :render, :foo)
# obj.render(:foo => "Hello!") #=> "<p>Hello!</p>"
#
# # This doesn't
# obj = Object.new
# Haml::Engine.new("%p= foo").def_method(obj, :render)
# obj.render(:foo => "Hello!") #=> NameError: undefined local variable or method `foo'
#
# Note that Haml modifies the evaluation context
# (either the scope object or the `self` object of the scope binding).
# It extends {Haml::Helpers}, and various instance variables are set
# (all prefixed with `haml_`).
#
# @param object [Object, Module] The object on which to define the method
# @param name [String, Symbol] The name of the method to define
# @param local_names [Array<Symbol>] The names of the locals that can be passed to the proc
def def_method(object, name, *local_names)
method = object.is_a?(Module) ? :module_eval : :instance_eval
object.send(method, "def #{name}(_haml_locals = {}); #{precompiled_with_ambles(local_names)}; end",
@options[:filename], @options[:line])
end
protected
# Returns a subset of \{#options}: those that {Haml::Buffer} cares about.
# All of the values here are such that when `#inspect` is called on the hash,
# it can be `Kernel#eval`ed to get the same result back.
#
# See {file:HAML_REFERENCE.md#haml_options the Haml options documentation}.
#
# @return [{Symbol => Object}] The options hash
def options_for_buffer
{
:autoclose => @options[:autoclose],
:preserve => @options[:preserve],
:attr_wrapper => @options[:attr_wrapper],
:ugly => @options[:ugly],
:format => @options[:format],
:encoding => @options[:encoding],
:escape_html => @options[:escape_html],
}
end
private
def set_locals(locals, scope, scope_object)
scope_object.send(:instance_variable_set, '@_haml_locals', locals)
set_locals = locals.keys.map { |k| "#{k} = @_haml_locals[#{k.inspect}]" }.join("\n")
eval(set_locals, scope)
end
end
end